mm: thp: check pmd migration entry in common path
When THP migration is being used, memory management code needs to handle pmd migration entries properly. This patch uses !pmd_present() or is_swap_pmd() (depending on whether pmd_none() needs separate code or not) to check pmd migration entries at the places where a pmd entry is present. Since pmd-related code uses split_huge_page(), split_huge_pmd(), pmd_trans_huge(), pmd_trans_unstable(), or pmd_none_or_trans_huge_or_clear_bad(), this patch: 1. adds pmd migration entry split code in split_huge_pmd(), 2. takes care of pmd migration entries whenever pmd_trans_huge() is present, 3. makes pmd_none_or_trans_huge_or_clear_bad() pmd migration entry aware. Since split_huge_page() uses split_huge_pmd() and pmd_trans_unstable() is equivalent to pmd_none_or_trans_huge_or_clear_bad(), we do not change them. Until this commit, a pmd entry should be: 1. pointing to a pte page, 2. is_swap_pmd(), 3. pmd_trans_huge(), 4. pmd_devmap(), or 5. pmd_none(). Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Nellans <dnellans@nvidia.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Zi Yan
Linus Torvalds
Родитель
616b837153
Коммит
84c3fc4e9c
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@ -608,7 +608,8 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
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ptl = pmd_trans_huge_lock(pmd, vma);
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if (ptl) {
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smaps_pmd_entry(pmd, addr, walk);
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if (pmd_present(*pmd))
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smaps_pmd_entry(pmd, addr, walk);
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spin_unlock(ptl);
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return 0;
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}
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@ -1012,6 +1013,9 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
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goto out;
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}
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if (!pmd_present(*pmd))
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goto out;
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page = pmd_page(*pmd);
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/* Clear accessed and referenced bits. */
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@ -1293,27 +1297,33 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
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if (ptl) {
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u64 flags = 0, frame = 0;
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pmd_t pmd = *pmdp;
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struct page *page = NULL;
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if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(pmd))
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flags |= PM_SOFT_DIRTY;
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/*
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* Currently pmd for thp is always present because thp
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* can not be swapped-out, migrated, or HWPOISONed
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* (split in such cases instead.)
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* This if-check is just to prepare for future implementation.
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*/
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if (pmd_present(pmd)) {
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struct page *page = pmd_page(pmd);
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if (page_mapcount(page) == 1)
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flags |= PM_MMAP_EXCLUSIVE;
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page = pmd_page(pmd);
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flags |= PM_PRESENT;
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if (pm->show_pfn)
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frame = pmd_pfn(pmd) +
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((addr & ~PMD_MASK) >> PAGE_SHIFT);
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}
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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else if (is_swap_pmd(pmd)) {
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swp_entry_t entry = pmd_to_swp_entry(pmd);
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frame = swp_type(entry) |
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(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
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flags |= PM_SWAP;
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VM_BUG_ON(!is_pmd_migration_entry(pmd));
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page = migration_entry_to_page(entry);
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}
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#endif
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if (page && page_mapcount(page) == 1)
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flags |= PM_MMAP_EXCLUSIVE;
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for (; addr != end; addr += PAGE_SIZE) {
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pagemap_entry_t pme = make_pme(frame, flags);
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@ -846,7 +846,23 @@ static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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barrier();
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#endif
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if (pmd_none(pmdval) || pmd_trans_huge(pmdval))
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/*
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* !pmd_present() checks for pmd migration entries
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*
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* The complete check uses is_pmd_migration_entry() in linux/swapops.h
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* But using that requires moving current function and pmd_trans_unstable()
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* to linux/swapops.h to resovle dependency, which is too much code move.
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*
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* !pmd_present() is equivalent to is_pmd_migration_entry() currently,
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* because !pmd_present() pages can only be under migration not swapped
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* out.
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*
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* pmd_none() is preseved for future condition checks on pmd migration
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* entries and not confusing with this function name, although it is
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* redundant with !pmd_present().
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*/
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if (pmd_none(pmdval) || pmd_trans_huge(pmdval) ||
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(IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval)))
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return 1;
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if (unlikely(pmd_bad(pmdval))) {
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pmd_clear_bad(pmd);
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@ -147,7 +147,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
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#define split_huge_pmd(__vma, __pmd, __address) \
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do { \
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pmd_t *____pmd = (__pmd); \
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if (pmd_trans_huge(*____pmd) \
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if (is_swap_pmd(*____pmd) || pmd_trans_huge(*____pmd) \
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|| pmd_devmap(*____pmd)) \
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__split_huge_pmd(__vma, __pmd, __address, \
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false, NULL); \
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@ -178,12 +178,18 @@ extern spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd,
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struct vm_area_struct *vma);
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extern spinlock_t *__pud_trans_huge_lock(pud_t *pud,
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struct vm_area_struct *vma);
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static inline int is_swap_pmd(pmd_t pmd)
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{
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return !pmd_none(pmd) && !pmd_present(pmd);
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}
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/* mmap_sem must be held on entry */
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static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
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struct vm_area_struct *vma)
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{
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VM_BUG_ON_VMA(!rwsem_is_locked(&vma->vm_mm->mmap_sem), vma);
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if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
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if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
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return __pmd_trans_huge_lock(pmd, vma);
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else
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return NULL;
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@ -299,6 +305,10 @@ static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
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long adjust_next)
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{
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}
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static inline int is_swap_pmd(pmd_t pmd)
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{
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return 0;
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}
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static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
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struct vm_area_struct *vma)
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{
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22
mm/gup.c
22
mm/gup.c
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@ -234,6 +234,16 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
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return page;
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return no_page_table(vma, flags);
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}
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retry:
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if (!pmd_present(*pmd)) {
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if (likely(!(flags & FOLL_MIGRATION)))
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return no_page_table(vma, flags);
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VM_BUG_ON(thp_migration_supported() &&
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!is_pmd_migration_entry(*pmd));
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if (is_pmd_migration_entry(*pmd))
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pmd_migration_entry_wait(mm, pmd);
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goto retry;
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}
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if (pmd_devmap(*pmd)) {
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ptl = pmd_lock(mm, pmd);
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page = follow_devmap_pmd(vma, address, pmd, flags);
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@ -247,7 +257,15 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
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if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
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return no_page_table(vma, flags);
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retry_locked:
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ptl = pmd_lock(mm, pmd);
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if (unlikely(!pmd_present(*pmd))) {
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spin_unlock(ptl);
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if (likely(!(flags & FOLL_MIGRATION)))
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return no_page_table(vma, flags);
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pmd_migration_entry_wait(mm, pmd);
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goto retry_locked;
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}
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if (unlikely(!pmd_trans_huge(*pmd))) {
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spin_unlock(ptl);
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return follow_page_pte(vma, address, pmd, flags);
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@ -424,7 +442,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
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pud = pud_offset(p4d, address);
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BUG_ON(pud_none(*pud));
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pmd = pmd_offset(pud, address);
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if (pmd_none(*pmd))
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if (!pmd_present(*pmd))
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return -EFAULT;
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VM_BUG_ON(pmd_trans_huge(*pmd));
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pte = pte_offset_map(pmd, address);
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@ -1534,7 +1552,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
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pmd_t pmd = READ_ONCE(*pmdp);
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next = pmd_addr_end(addr, end);
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if (pmd_none(pmd))
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if (!pmd_present(pmd))
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return 0;
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if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd))) {
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@ -928,6 +928,23 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
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ret = -EAGAIN;
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pmd = *src_pmd;
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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if (unlikely(is_swap_pmd(pmd))) {
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swp_entry_t entry = pmd_to_swp_entry(pmd);
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VM_BUG_ON(!is_pmd_migration_entry(pmd));
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if (is_write_migration_entry(entry)) {
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make_migration_entry_read(&entry);
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pmd = swp_entry_to_pmd(entry);
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set_pmd_at(src_mm, addr, src_pmd, pmd);
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}
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set_pmd_at(dst_mm, addr, dst_pmd, pmd);
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ret = 0;
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goto out_unlock;
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}
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#endif
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if (unlikely(!pmd_trans_huge(pmd))) {
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pte_free(dst_mm, pgtable);
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goto out_unlock;
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@ -1599,6 +1616,12 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
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if (is_huge_zero_pmd(orig_pmd))
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goto out;
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if (unlikely(!pmd_present(orig_pmd))) {
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VM_BUG_ON(thp_migration_supported() &&
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!is_pmd_migration_entry(orig_pmd));
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goto out;
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}
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page = pmd_page(orig_pmd);
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/*
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* If other processes are mapping this page, we couldn't discard
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@ -1810,6 +1833,25 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
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preserve_write = prot_numa && pmd_write(*pmd);
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ret = 1;
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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if (is_swap_pmd(*pmd)) {
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swp_entry_t entry = pmd_to_swp_entry(*pmd);
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VM_BUG_ON(!is_pmd_migration_entry(*pmd));
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if (is_write_migration_entry(entry)) {
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pmd_t newpmd;
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/*
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* A protection check is difficult so
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* just be safe and disable write
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*/
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make_migration_entry_read(&entry);
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newpmd = swp_entry_to_pmd(entry);
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set_pmd_at(mm, addr, pmd, newpmd);
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}
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goto unlock;
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}
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#endif
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/*
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* Avoid trapping faults against the zero page. The read-only
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* data is likely to be read-cached on the local CPU and
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@ -1875,7 +1917,8 @@ spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
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{
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spinlock_t *ptl;
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ptl = pmd_lock(vma->vm_mm, pmd);
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if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd)))
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if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) ||
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pmd_devmap(*pmd)))
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return ptl;
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spin_unlock(ptl);
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return NULL;
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@ -1993,14 +2036,15 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
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struct page *page;
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pgtable_t pgtable;
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pmd_t _pmd;
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bool young, write, dirty, soft_dirty;
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bool young, write, dirty, soft_dirty, pmd_migration = false;
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unsigned long addr;
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int i;
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VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);
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VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
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VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);
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VM_BUG_ON(!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd));
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VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd)
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&& !pmd_devmap(*pmd));
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count_vm_event(THP_SPLIT_PMD);
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@ -2025,7 +2069,16 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
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return __split_huge_zero_page_pmd(vma, haddr, pmd);
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}
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page = pmd_page(*pmd);
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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pmd_migration = is_pmd_migration_entry(*pmd);
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if (pmd_migration) {
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swp_entry_t entry;
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entry = pmd_to_swp_entry(*pmd);
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page = pfn_to_page(swp_offset(entry));
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} else
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#endif
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page = pmd_page(*pmd);
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VM_BUG_ON_PAGE(!page_count(page), page);
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page_ref_add(page, HPAGE_PMD_NR - 1);
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write = pmd_write(*pmd);
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@ -2044,7 +2097,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
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* transferred to avoid any possibility of altering
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* permissions across VMAs.
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*/
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if (freeze) {
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if (freeze || pmd_migration) {
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swp_entry_t swp_entry;
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swp_entry = make_migration_entry(page + i, write);
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entry = swp_entry_to_pte(swp_entry);
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@ -2143,7 +2196,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
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page = pmd_page(*pmd);
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if (PageMlocked(page))
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clear_page_mlock(page);
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} else if (!pmd_devmap(*pmd))
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} else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd)))
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goto out;
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__split_huge_pmd_locked(vma, pmd, haddr, freeze);
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out:
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|
|
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@ -4664,6 +4664,11 @@ static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
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struct page *page = NULL;
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enum mc_target_type ret = MC_TARGET_NONE;
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if (unlikely(is_swap_pmd(pmd))) {
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VM_BUG_ON(thp_migration_supported() &&
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!is_pmd_migration_entry(pmd));
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return ret;
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}
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page = pmd_page(pmd);
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VM_BUG_ON_PAGE(!page || !PageHead(page), page);
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if (!(mc.flags & MOVE_ANON))
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12
mm/memory.c
12
mm/memory.c
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@ -1065,7 +1065,8 @@ static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src
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src_pmd = pmd_offset(src_pud, addr);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_trans_huge(*src_pmd) || pmd_devmap(*src_pmd)) {
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if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd)
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|| pmd_devmap(*src_pmd)) {
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int err;
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VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, vma);
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err = copy_huge_pmd(dst_mm, src_mm,
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@ -1326,7 +1327,7 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
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pmd = pmd_offset(pud, addr);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
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if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
|
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if (next - addr != HPAGE_PMD_SIZE) {
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VM_BUG_ON_VMA(vma_is_anonymous(vma) &&
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!rwsem_is_locked(&tlb->mm->mmap_sem), vma);
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@ -3911,6 +3912,13 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
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pmd_t orig_pmd = *vmf.pmd;
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|
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barrier();
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if (unlikely(is_swap_pmd(orig_pmd))) {
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VM_BUG_ON(thp_migration_supported() &&
|
||||
!is_pmd_migration_entry(orig_pmd));
|
||||
if (is_pmd_migration_entry(orig_pmd))
|
||||
pmd_migration_entry_wait(mm, vmf.pmd);
|
||||
return 0;
|
||||
}
|
||||
if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
|
||||
if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
|
||||
return do_huge_pmd_numa_page(&vmf, orig_pmd);
|
||||
|
|
|
|||
|
|
@ -149,7 +149,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
|
|||
unsigned long this_pages;
|
||||
|
||||
next = pmd_addr_end(addr, end);
|
||||
if (!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)
|
||||
if (!is_swap_pmd(*pmd) && !pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)
|
||||
&& pmd_none_or_clear_bad(pmd))
|
||||
continue;
|
||||
|
||||
|
|
@ -159,7 +159,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
|
|||
mmu_notifier_invalidate_range_start(mm, mni_start, end);
|
||||
}
|
||||
|
||||
if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
|
||||
if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
|
||||
if (next - addr != HPAGE_PMD_SIZE) {
|
||||
__split_huge_pmd(vma, pmd, addr, false, NULL);
|
||||
} else {
|
||||
|
|
|
|||
|
|
@ -223,7 +223,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
|
|||
new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr);
|
||||
if (!new_pmd)
|
||||
break;
|
||||
if (pmd_trans_huge(*old_pmd)) {
|
||||
if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) {
|
||||
if (extent == HPAGE_PMD_SIZE) {
|
||||
bool moved;
|
||||
/* See comment in move_ptes() */
|
||||
|
|
|
|||
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